Probably an exaggeration. Novak Djokovic still has a good margin to stay inside the top 5 next year I think.Djokovic will probably dissapear on some cloud of love in 2017... he is done as a tennis player I think .
That being said, I've heard people say Djokovic looks skinnier and less muscular, too – then we have to give credit to Murray for his athleticism. Anyway, I didn't hear too many say Djokovic appeared frail when he beat Kei Nishikori 6-1, 6-1 on Saturday night. Djokovic actually looked alright to me during his last tournament apart from the final but he was facing Andy Murray to whom he already lost several big finals in the past. No reason to see Djokovic out of the top 5 just yet.